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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #382451
Research Project: Discovery and Development of Microbial-Based Biological Control Agents for Use Against Invasive Weeds in the United States

Location: Foreign Disease-Weed Science Research

Title: Soil nutrient inputs shift endophytic phenotypes in a manner consistent with a significant role for species interactions in community assembly

Author
item Fulcher, Michael
item SPAWN-LEE, SETH - University Of Wisconsin
item HANSEN, ZOE - Michigan State University
item JOHNSON, MITCH - University Of Minnesota
item ZEWEI, SONG - Bgi Shenzhen
item MAY, GEORGIANA - University Of Minnesota
item SEABLOOM, ERIC - University Of Minnesota
item BORER, ELIZABETH - University Of Minnesota
item KINKEL, LINDA - University Of Minnesota

Submitted to: Ecological Society of America (ESA)
Publication Type: Abstract Only
Publication Acceptance Date: 4/13/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: 1) Background/Question/Methods Endophytic microbes influence plant health and productivity in both natural and agricultural environments, but their community assembly processes remain poorly understood. We studied the response of foliar endophyte communities in a natural grassland to eight years of annual nitrogen, phosphorous and potassium (NPK) amendment. Bacterial and fungal endophytes were isolated from healthy leaves (n=6 per treatment, NPK-amended or control) of Andropogon gerardii. A random collection of isolates (n=120 bacteria and fungi each, 10 of each kingdom from each leaf) were assigned to genus based on 16S or ITS2 sequence similarity and characterized for nutrient utilization with Biolog SF-P2 plates. Network analysis was used to quantify resource competition between sympatric isolates. Inhibition of a collection of indicator microbes was also recorded for all fungal isolates in vitro. 2) Results/Conclusions Fungal, but not bacterial, community composition, nutrient utilization and inhibitory phenotypes varied dramatically between NPK and control treatments. Phylogenetic analysis showed both intra- and intergenic differentiation between treatments. The growth efficiency of fungi was greater in control leaves for five of seven nutrient classes, but fungi from NPK-amended leaves exhibited greater growth efficiency on aromatic and P-rich compounds. Fungal niche width was significantly greater than bacterial niche width in control leaves, but this advantage disappeared in NPK-amended leaves. The loss of this fungal competitive advantage was associated with increased inhibition strength against bacteria. Network analyses revealed fungal isolates that were the weakest competitors for nutrients (high node in-degree) produced significantly larger zones of inhibition against bacteria than strong nutrient competitors. Our results show widely applied soil nutrients alter the structure and function of endophyte communities. Moreover, the data suggest roles for resource competition and antagonistic microbial interactions in the endophytic community assembly process.